292 research outputs found

    Sobrecarga virtual equivalente para Puentes Carreteros

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    EFFICACY AND TOLERABILITY OF LERCANIDIPINE IN ELDERLY PATIENTS WITH MILD TO MODERATE HYPERTENSION IN A PLACEBO-CONTROLLED, DOUBLE-BLIND STUDY

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    Цель. Оценить эффективность лерканидипина (антагониста кальция из группы дигидропиридинов) у пожилых больных артериальной гипертонией (АГ). Материал и методы. В многоцентровое рандомизированное двойное слепое плацебо-контролируемое исследование включены 144 больных в возрасте 60-85 лет, разделенных на группы, получавших лерканидипин в дозе 10 мг или плацебо в течение 4 нед. При недостаточной антигипертензивной эффективности исходную дозу лерканидипина увеличивали (вплоть до 30 мг один раз/день в течение 12 нед).  Результаты. Диастолическое артериальное давление (АД) под действием лерканидипина в дозе 10 мг снижалось в большей степени (-10,3 мм рт.ст.), чем под действием плацебо (-6,1 мм рт.ст.; p<0,05). Доля больных, положительно ответивших на прием лерканидипина, также была выше, чем при приеме плацебо (59,1% и 37,8 %, соответственно; p<0,05). При увеличении дозы препарата до 20 мг доля больных, положительно ответивших на лечение, возросла до 69,4%; увеличение дозы до 30 мг потребовалось лишь небольшому числу пациентов. Частота сердечных сокращений и лабораторные показатели на фоне лечения не менялись. Процент больных с побочными эффектами был одинаковым в обеих группах. Заключение. Прием лерканидипина один раз в день значительно снижает АД у пожилых пациентов с легкой и умеренной АГ . Эффект сохраняется в течение 24 ч и не сопровождается рефлекторной тахикардией. Препарат хорошо переносится и, учитывая его фармакологические и фармакодинамические особенности, может быть рекомендован, особенно пожилым пациентам

    The artificial retina processor for track reconstruction at the LHC crossing rate

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    We present results of an R&D study for a specialized processor capable of precisely reconstructing, in pixel detectors, hundreds of charged-particle tracks from high-energy collisions at 40 MHz rate. We apply a highly parallel pattern-recognition algorithm, inspired by studies of the processing of visual images by the brain as it happens in nature, and describe in detail an efficient hardware implementation in high-speed, high-bandwidth FPGA devices. This is the first detailed demonstration of reconstruction of offline-quality tracks at 40 MHz and makes the device suitable for processing Large Hadron Collider events at the full crossing frequency.Comment: 4th draft of WIT proceedings modified according to JINST referee's comments. 10 pages, 6 figures, 2 table

    Observation of J/ψpJ/\psi p resonances consistent with pentaquark states in Λb0J/ψKp{\Lambda_b^0\to J/\psi K^-p} decays

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    Observations of exotic structures in the J/ψpJ/\psi p channel, that we refer to as pentaquark-charmonium states, in Λb0J/ψKp\Lambda_b^0\to J/\psi K^- p decays are presented. The data sample corresponds to an integrated luminosity of 3/fb acquired with the LHCb detector from 7 and 8 TeV pp collisions. An amplitude analysis is performed on the three-body final-state that reproduces the two-body mass and angular distributions. To obtain a satisfactory fit of the structures seen in the J/ψpJ/\psi p mass spectrum, it is necessary to include two Breit-Wigner amplitudes that each describe a resonant state. The significance of each of these resonances is more than 9 standard deviations. One has a mass of 4380±8±294380\pm 8\pm 29 MeV and a width of 205±18±86205\pm 18\pm 86 MeV, while the second is narrower, with a mass of 4449.8±1.7±2.54449.8\pm 1.7\pm 2.5 MeV and a width of 39±5±1939\pm 5\pm 19 MeV. The preferred JPJ^P assignments are of opposite parity, with one state having spin 3/2 and the other 5/2.Comment: 48 pages, 18 figures including the supplementary material, v2 after referee's comments, now 19 figure

    Search for hidden-sector bosons in B0 ⁣K0μ+μB^0 \!\to K^{*0}\mu^+\mu^- decays

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    A search is presented for hidden-sector bosons, χ\chi, produced in the decay B0 ⁣K(892)0χ{B^0\!\to K^*(892)^0\chi}, with K(892)0 ⁣K+πK^*(892)^0\!\to K^{+}\pi^{-} and χ ⁣μ+μ\chi\!\to\mu^+\mu^-. The search is performed using pppp-collision data corresponding to 3.0 fb1^{-1} collected with the LHCb detector. No significant signal is observed in the accessible mass range 214m(χ)4350214 \leq m({\chi}) \leq 4350 MeV, and upper limits are placed on the branching fraction product B(B0 ⁣K(892)0χ)×B(χ ⁣μ+μ)\mathcal{B}(B^0\!\to K^*(892)^0\chi)\times\mathcal{B}(\chi\!\to\mu^+\mu^-) as a function of the mass and lifetime of the χ\chi boson. These limits are of the order of 10910^{-9} for χ\chi lifetimes less than 100 ps over most of the m(χ)m(\chi) range, and place the most stringent constraints to date on many theories that predict the existence of additional low-mass bosons.Comment: All figures and tables, along with supplementary material, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-036.htm

    Measurement of the branching fraction ratio B(Bc+ψ(2S)π+)/B(Bc+J/ψπ+)\mathcal{B}(B_c^+ \rightarrow \psi(2S)\pi^+)/\mathcal{B}(B_c^+ \rightarrow J/\psi \pi^+)

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    Using pppp collision data collected by LHCb at center-of-mass energies s\sqrt{s} = 7 TeV and 8 TeV, corresponding to an integrated luminosity of 3 fb1^{-1}, the ratio of the branching fraction of the Bc+ψ(2S)π+B_c^+ \rightarrow \psi(2S)\pi^+ decay relative to that of the Bc+J/ψπ+B_c^+ \rightarrow J/\psi\pi^+ decay is measured to be 0.268 ±\pm 0.032 (stat) ±\pm 0.007 (syst) ±\pm 0.006 (BF). The first uncertainty is statistical, the second is systematic, and the third is due to the uncertainties on the branching fractions of the J/ψμ+μJ/\psi \rightarrow \mu^+\mu^- and ψ(2S)μ+μ\psi(2S) \rightarrow \mu^+\mu^- decays. This measurement is consistent with the previous LHCb result, and the statistical uncertainty is halved.Comment: 17 pages including author list, 2 figure

    Study of BDKπ+πB^{-}\to DK^-\pi^+\pi^- and BDππ+πB^-\to D\pi^-\pi^+\pi^- decays and determination of the CKM angle γ\gamma

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    We report a study of the suppressed BDKπ+πB^-\to DK^-\pi^+\pi^- and favored BDππ+πB^-\to D\pi^-\pi^+\pi^- decays, where the neutral DD meson is detected through its decays to the Kπ±K^{\mp}\pi^{\pm} and CP-even K+KK^+K^- and π+π\pi^+\pi^- final states. The measurement is carried out using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 3.0~fb1^{-1}. We observe the first significant signals in the CP-even final states of the DD meson for both the suppressed BDKπ+πB^-\to DK^-\pi^+\pi^- and favored BDππ+πB^-\to D\pi^-\pi^+\pi^- modes, as well as in the doubly Cabibbo-suppressed DK+πD\to K^+\pi^- final state of the BDππ+πB^-\to D\pi^-\pi^+\pi^- decay. Evidence for the ADS suppressed decay BDKπ+πB^{-}\to DK^-\pi^+\pi^-, with DK+πD\to K^+\pi^-, is also presented. From the observed yields in the BDKπ+πB^-\to DK^-\pi^+\pi^-, BDππ+πB^-\to D\pi^-\pi^+\pi^- and their charge conjugate decay modes, we measure the value of the weak phase to be γ=(7419+20)o\gamma=(74^{+20}_{-19})^{\rm o}. This is one of the most precise single-measurement determinations of γ\gamma to date.Comment: 22 pages, 9 figures; All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-020.htm

    Study of WW boson production in association with beauty and charm

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    The associated production of a WW boson with a jet originating from either a light parton or heavy-flavor quark is studied in the forward region using proton-proton collisions. The analysis uses data corresponding to integrated luminosities of 1.0 and 2.0fb12.0\,{\rm fb}^{-1} collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, respectively. The WW bosons are reconstructed using the WμνW\to\mu\nu decay and muons with a transverse momentum, pTp_{\rm T}, larger than 20 GeV in the pseudorapidity range 2.0202.0 20 GeV and 2.2<η<4.22.2 < \eta < 4.2. The sum of the muon and jet momenta must satisfy pT>20p_{\rm T} > 20 GeV. The fraction of W+W+jet events that originate from beauty and charm quarks is measured, along with the charge asymmetries of the W ⁣+ ⁣bW\!+\!b and W ⁣+ ⁣cW\!+\!c production cross-sections. The ratio of the W+W+jet to Z+Z+jet production cross-sections is also measured using the ZμμZ\to\mu\mu decay. All results are in agreement with Standard Model predictions

    Amplitude analysis of B0Dˉ0K+πB^0 \rightarrow \bar{D}^0 K^+ \pi^- decays

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    The Dalitz plot distribution of B0Dˉ0K+πB^0 \rightarrow \bar{D}^0 K^+ \pi^- decays is studied using a data sample corresponding to 3.0fb13.0\rm{fb}^{-1} of pppp collision data recorded by the LHCb experiment during 2011 and 2012. The data are described by an amplitude model that contains contributions from intermediate K(892)0K^*(892)^0, K(1410)0K^*(1410)^0, K2(1430)0K^*_2(1430)^0 and D2(2460)D^*_2(2460)^- resonances. The model also contains components to describe broad structures, including the K0(1430)0K^*_0(1430)^0 and D0(2400)D^*_0(2400)^- resonances, in the KπK\pi S-wave and the DπD\pi S- and P-waves. The masses and widths of the D0(2400)D^*_0(2400)^- and D2(2460)D^*_2(2460)^- resonances are measured, as are the complex amplitudes and fit fractions for all components included in the amplitude model. The model obtained will be an integral part of a future determination of the angle γ\gamma of the CKM quark mixing matrix using B0DK+πB^0 \rightarrow D K^+ \pi^- decays.Comment: 33 pages, 12 figures; updated for publicatio

    Measurement of the ratio of branching fractions B(B0D+τντ)/B(B0D+μνμ)\mathcal{B}(\overline{B}^0 \to D^{*+}\tau^{-}\overline{\nu}_{\tau})/\mathcal{B}(\overline{B}^0 \to D^{*+}\mu^{-}\overline{\nu}_{\mu})

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    The branching fraction ratio R(D)B(B0D+τντ)/B(B0D+μνμ)\mathcal{R}(D^{*}) \equiv \mathcal{B}(\overline{B}^0 \to D^{*+}\tau^{-}\overline{\nu}_{\tau})/\mathcal{B}(\overline{B}^0 \to D^{*+}\mu^{-}\overline{\nu}_{\mu}) is measured using a sample of proton-proton collision data corresponding to 3.0\invfb of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τμνμντ\tau^{-} \to \mu^{-}\overline{\nu}_{\mu}\nu_{\tau}. The semitauonic decay is sensitive to contributions from non-Standard-Model particles that preferentially couple to the third generation of fermions, in particular Higgs-like charged scalars. A multidimensional fit to kinematic distributions of the candidate B0\overline{B}^0 decays gives R(D)=0.336±0.027(stat)±0.030(syst)\mathcal{R}(D^{*}) = 0.336 \pm 0.027(stat) \pm 0.030 (syst). This result, which is the first measurement of this quantity at a hadron collider, is 2.12.1 standard deviations larger than the value expected from lepton universality in the Standard Model.Comment: 17 pages, 1 figure. v2 after referees' comment
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